About to use my BMG (received after a very bad experience - don't ask). I know as repeatedly confirmed by many on this thread that the certificate is valid for standard room only so booked one (flex rate) for a date in two weeks. However, is the BMG compatible with e-standby upgrades? i.e. could I select the e-stanby upgrade, check in with my certificate and only pay the upgrade cost at check in? Many thanks!